NR AQRG
AU Hayashi,H.K.; Takata,M.; Iwamaru,Y.; Ushiki,Y.K.; Kimura,K.M.; Tagawa,Y.; Shinagawa,M.; Yokoyama,T.
TI Effect of tissue deterioration on postmortem BSE diagnosis by immunobiochemical detection of an abnormal isoform of prion protein
QU Journal of Veterinary Medical Science 2004 May; 66(5): 515-20
PT journal article
AB Surveillance for bovine spongiform encephalopathy (BSE) in fallen stock in Japan is conducted with a commercial enzyme-linked immunosorbent assay (ELISA) for mass screening, with Western blotting (WB) and immunohistochemistry performed for confirmation of the ELISA. All tests are based on immunological detection of an abnormal isoform of the prion protein (PrPsc) in brain tissues, which have sometimes deteriorated by the time samples from fallen stock reach a diagnostic laboratory. To evaluate BSE surveillance procedures for fallen stock, we examined PrPsc detection from artificially deteriorated BSE-affected bovine brain tissues with a commercial ELISA kit and compared the results with those of WB. The optical density (OD) values of the ELISA decreased with advancing deterioration of the tissues, whereas no reduction in the signal for PrPsc was observed in WB, even when performed after 4 days of incubation at 37 degrees C. The progressive decrease in the OD values in the ELISA appear to be caused by a partial loss of the N-terminal moiety of PrPsc due to digestion by endogeneous and/or contaminated microbial enzymes, and by the presence of ELISA inhibitors that are generated in deteriorated tissues. These results suggest that WB is the most reliable test for fallen stock, especially for cattle brains within decaying carcasses.
IN Die Autoren inkubierten Hirngewebe von BSE-Rindern tagelang bei 37° und stellten fest, dass zumindest über einen Zeitraum von 4 Tagen beim Prionics Western blot keine sichtbare Abnahme der Bandenstärke auftrat. Im BioRad-ELISA hingegen nahm die Signalstärke mit zunehmender Autolyse der Proben immer stärker ab. Die Autoren meinen, die Aminotermini würden durch endogene oder mikrobielle Proteasen zunehmend abgebaut und dies beeinträchtige besonders den BioRad-Test. Mir erscheint diese Erklärung zweifelhaft, weil gerade der BioRad-ELISA die geringsten Probleme mit den besonders Protease-sensitiven Scrapie-Fällen hatte [AQGX]. Die Autoren meinen aber auch, der BioRad-ELISA werde durch Inhibitoren beeinträchtigt, welche durch die Autolyse entstehen.
MH Animals; Blotting, Western/veterinary; Brain/*pathology; Cattle; Cattle Diseases/*diagnosis/pathology; Comparative Study; Encephalopathy, Bovine Spongiform/*diagnosis/pathology; Enzyme-Linked Immunosorbent Assay/veterinary; Immunohistochemistry/veterinary; *Postmortem Changes; Prions/*isolation & purification; Support, Non-U.S. Gov't
AD Prion Disease Research Center, National Institute of Animal Health, Tsukuba, Ibaraki, Japan.
SP englisch
PO Japan
ZF Zusammenfassung des Abstracts von Roland Heynkes